statdx/docs_md/articles/vessel-wall-abnormalities_850dc563-30b3-4627-87bc-fd858bccf896.md

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Vessel Wall Abnormalities	850dc563-30b3-4627-87bc-fd858bccf896	key value 2bca6b86-1eca-4e93-b997-4e18913686a7 Hediyeh Baradaran, MD, MS key value f6dcad15-b660-4243-a242-a9845c929101 J. Scott McNally, MD, PhD	name slug treeNodeId Brain brain 6d8829f1-14d7-45af-8675-255189aa526a name slug treeNodeId Differential Diagnosis differential-diagnosis a7fdd139-664e-4bb8-8d18-400e4733ff60 name slug treeNodeId Arteries arteries f5fee8ee-062f-41f2-b449-efcca9fb78f9 name slug treeNodeId Anatomically Based Differentials anatomically-based-differentials 9955b05e-9840-401a-b3da-4039f8b22a35 name slug treeNodeId Vessel Wall Abnormalities vessel-wall-abnormalities null	Brain	9cf47507-a8f6-447a-8848-ac23bd794e2d	18	02/22/23	Vessel Wall Abnormalities	Brain, Differential Diagnosis, Arteries, Anatomically Based Differentials, Vessel Wall Abnormalities	Vessel Wall Abnormalities | STATdx	Vessel Wall Abnormalities	DDX	true	Brain Differential Diagnosis Arteries Anatomically Based Differentials Vessel Wall Abnormalities

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title: "Vessel Wall Abnormalities" docid: "850dc563-30b3-4627-87bc-fd858bccf896" authors:

• key: "2bca6b86-1eca-4e93-b997-4e18913686a7" value: "Hediyeh Baradaran, MD, MS"
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ESSENTIAL INFORMATION

• Key Differential Diagnosis Issues

  • Clinical history - History can narrow DDx, but it is often absent initially
  • Stroke - DDx includes extra/intracranial atherosclerosis, dissection, vasospasm, reversible cerebral vasoconstriction syndrome (RCVS)
  • Subarachnoid hemorrhage (SAH) - DDx includes aneurysm (or other vascular lesion/arteriovenous malformation) vs. RCVS vs. vasculitis
  • Imaging can narrow differential, guide treatment - Vessel wall MR (vwMR) protocol - 3T MR, sub mm, 3D volumetric images - Precontrast: Time of flight (TOF), T2 SPACE, DANTE T1 SPACE, MPRAGE - Postcontrast: DANTE T1 SPACE, TOF

• Helpful Clues for Common Diagnoses

  • Atherosclerosis, Extracranial - Location - Usually at branch points (e.g., carotid bifurcations) - Oscillatory shear stress at branch points predisposes to endothelial dysfunction and atrioventricular septal defect (ASVD) - Lumen imaging (CTA or MRA) - Plaque thickness - Positive remodeling occurs prior to stenosis - Increased soft plaque → lipid → necrosis → intraplaque hemorrhage - Stenosis - Carotid stenosis is measured by North American Symptomatic Carotid Endarterectomy Trial (NASCET) (a-b)/a: "a" = diameter of downstream ICA, and "b" = diameter at level of stenosis - Watch for near occlusion [e.g., downstream ICA < 3 mm or < external carotid artery (ECA)] - Millimeter stenosis measurement can also be used - Ulceration - CTA has high accuracy for detecting ulcerations measuring > 2 mm - Intraluminal thrombus - Rare, but if present, highly associated with acute infarction (positive predictive value: ~ 1) - Identified by donut sign on CTA or MRA - Calcification - Indicates atherosclerosis - Calcification itself may be stable but often adjacent to unstable components - Calcification pattern can indicate unstable plaque (e.g., spotty calcification) - Thin, adventitial calcification (< 2 mm) coupled with thick, soft plaque (> 2 mm) (rim sign) is associated with intraplaque hemorrhage - vwMR - Carotid intraplaque hemorrhage - American Heart Association (AHA) type VIb plaque (intraplaque rupture) - Highly associated with acute ipsilateral infarcts - High annual stroke risk (15-45%) despite medication - Best detected by heavily T1-weighted sequences; MPRAGE has ↑↑ signal-to-noise, spatial resolution, and accuracy compared to T1 FS or 3D TOF - MPRAGE-positive plaque: > 2x signal intensity of adjacent muscle, validated by histology - Lipid-rich necrotic core (LRNC) - Nonenhancing on DANTE T1 SPACE post contrast - Can also be detected as T2-hyperintense plaque - LRNC decreases after 1-2 years of statins - Fibrous cap (FC) - FC thinning (< 100 μm) or rupture indicates instability - FC (collagen-rich tissue) enhances on delayed T1 postcontrast black blood images, but detection of rupture can be difficult
  • Atherosclerosis, Intracranial - Location - Branch points predisposed - Proximal > distal branches - Lumen imaging - Focal stenosis, multifocal stenoses, lumen irregularities, ectasia - Stenosis measured by warfarin-aspirin symptomatic intracranial disease (WASID) criteria - vwMR - High T2 signal → lipid/necrotic core - High T1 signal → intraplaque hemorrhage (not as common as in extracranial plaque) - Enhancement → unstable/active atherosclerotic plaque - Highly associated with acute territorial stroke - High repeat stroke risk despite medical therapy (15-30% per year) - Calcification on CT/CTA → atherosclerosis
  • Dissection - Location - Extracranial > > intracranial - Vertebral > carotid arteries - Carotid arteries: Distal cervical ICAs > common carotid arteries (CCAs) - Vertebral arteries: V1/V3 > V2/V4 segments - Lumen imaging - Biffl grading system - Grade I: Mild irregularity with < 25% narrowing - Grade II: > 25% narrowing, dissection flap, intramural hematoma, or intraluminal thrombus - Grade III: Pseudoaneurysm - Grade IV: Occlusion - Grade V: Transection - vwMR - Intramural hematoma - Often, intramural hematoma is not present or detectable in dissection - T1-hyperintense signal indicates subacute dissection (methemoglobin) - Acute trauma: No T1-hyperintense signal and rarely hyperdense on CT
  • Vasospasm - Location - Usually, it is worst closest to source of SAH - Lumen imaging: Multifocal narrowing - vwMR: Negative = no T2 signal, no or mild enhancement
  • Aneurysm - Location - Occurs most often at branch points - If linear vessel segment, think pseudoaneurysm - Lumen imaging - Most often saccular - Irregularities and focal outpouchings more associated with instability - Rupture risk increases with size - vwMR - Wall enhancement associated with unstable aneurysm - Can identify SAH source if multiple aneurysms
  • Pseudoaneurysm - Location - Not often at branch points - Often adjacent to skull base fracture or dura - Common type is dorsal variant ICA blister aneurysm - Lumen imaging - Broad-based bulge, no neck, fusiform, irregular - Rapidly change in size over hours or days - vwMR - Avid wall enhancement at site of wall breakdown

• Helpful Clues for Less Common Diagnoses

  • Reversible Cerebral Vasoconstriction Syndrome - Location: Multifocal, diffuse - Lumen imaging: Multiple alternating stenoses - vwMR: Negative = no T2 signal, no or mild enhancement
  • Vasculitis - Location: Multifocal, diffuse - Lumen imaging: Multiple alternating stenoses - vwMR: Avid wall enhancement, no/mild T2 signal
  • Carotid Web - Location: Posterolateral carotid bifurcation - Lumen imaging: Linear filling defect

• Helpful Clues for Rare Diagnoses

  • Perivascular Infection - Location - Often direct spread from sinuses or mastoid air cells - Lumen imaging - Smooth or irregular stenosis - ± pseudoaneurysm, intraluminal thrombus - May require DSA for full delineation - vwMR: Wall enhancement with invasion
  • Perivascular Tumor - Location: Direct spread from adjacent tumor - Lumen imaging: Vessel narrowing, ± pseudoaneurysm, thrombus - vwMR: Thick, irregular wall enhancement

References

Selected References

1. El-Masri S et al: Systematic review and meta-analysis of ipsilateral and contralateral carotid web prevalence in embolic supratentorial strokes of undetermined source. J Clin Neurosci. 107:118-23, 2023
2. Chung CY et al: Imaging intracranial aneurysms in the endovascular era: surveillance and posttreatment follow-up. Radiographics. 42(3):789-805, 2022
3. Culleton S et al: MRI detection of carotid intraplaque hemorrhage and postintervention cognition. AJNR Am J Neuroradiol. 43(12):1762-9, 2022
4. Fanning NF et al: Thromboembolism from carotid web. Radiology. 221504, 2022
5. Larson AS et al: Nonstenotic carotid plaques and embolic stroke of undetermined source: a multimodality review. AJNR Am J Neuroradiol. ePub, 2022
6. Lehman VT et al: Conventional and high-resolution vessel wall MRI of intracranial aneurysms: current concepts and new horizons. J Neurosurg. 1-13, 2017
7. McNally JS et al: Magnetic resonance imaging detection of intraplaque hemorrhage. Magn Reson Insights. 10:1-8, 2017
8. Eisenmenger LB et al: Prediction of carotid intraplaque hemorrhage using adventitial calcification and plaque thickness on CTA. AJNR Am J Neuroradiol. 37(8):1496-503, 2016
9. McNally JS et al: Intraluminal thrombus, intraplaque hemorrhage, plaque thickness, and current smoking optimally predict carotid stroke. Stroke. 46(1):84-90, 2015
10. Mossa-Basha M et al: Multicontrast high-resolution vessel wall magnetic resonance imaging and its value in differentiating intracranial vasculopathic processes. Stroke. 46(6):1567-73, 2015
11. Bartlett ES et al: Quantification of carotid stenosis on CT angiography. AJNR Am J Neuroradiol. 27(1):13-9, 2006

Images

Selected Images

Atherosclerosis, Extracranial CTA shows a left carotid bifurcation/proximal ICA plaque. NASCET stenosis [(a-b)/a] is calculated by subtracting the maximal stenosis (b ) from the downstream normal-caliber ICA (a ) and normalizing to the downstream normal ICA (a). A single mm stenosis measurement (b) can alternatively be used. Maximum plaque thickness can also be measured on CTA .

Atherosclerosis, Extracranial CTA shows a left carotid bifurcation/proximal ICA plaque. NASCET stenosis [(a-b)/a] is calculated by subtracting the maximal stenosis (b ) from the downstream normal-caliber ICA (a ) and normalizing to the downstream normal ICA (a). A single mm stenosis measurement (b) can alternatively be used. Maximum plaque thickness can also be measured on CTA .

Atherosclerosis, Extracranial CTA (and MRA) can also detect ulceration (sagittal and axial ) and intraluminal thrombus (sagittal and axial ).

Atherosclerosis, Extracranial Intraplaque hemorrhage (IPH) can be detected on MRA. 3D TOF can detect IPH (sagittal and axial ), but TOF and conventional T1 FS MR are less accurate than MPRAGE when compared to histology.

Atherosclerosis, Extracranial While IPH is best detected with MR and heavily T1-weighted sequences, such as MPRAGE , IPH can be inferred on CTA with a rim sign , which consists of a thin, < 2-mm rim of calcification with ≥ 2-mm central soft plaque. Likelihood of IPH increases with soft plaque thickness.

Atherosclerosis, Intracranial DSA shows ~ 50% narrowing of the midbasilar artery in a patient with a pontine infarct. T2-hyperintense plaque on vwMR, IPH on MPRAGE , and wall enhancement on DANTE T1 SPACE indicate active plaque.

Dissection CTA shows traumatic dissection of the ICA with narrowing and associated intramural hematoma on MR . Intramural hematoma can be detected on MR using T1 FS MR or MPRAGE. Methemoglobin within intramural hematoma is T1 hyperintense.

Aneurysm MRA 3D TOF source image shows an anterior communicating artery saccular aneurysm . Vessel wall MR (vwMR) images show areas of wall enhancement comparing pre- and postcontrast DANTE T1 SPACE, thought to be linked to growth and rupture risk.

Pseudoaneurysm Dorsal variant ICA blister aneurysm, or pseudoaneurysm, is shown on DSA . Initial CTA shows mild lumen outpouching . vwMR shows that avid wall enhancement is present comparing pre- and postcontrast DANTE T1 SPACE.

Reversible Cerebral Vasoconstriction Syndrome Multifocal areas of narrowing are shown on DSA in a patient with thunderclap headache. Multifocal anterior circulation narrowing was also present (not shown). vwMR was negative. The patient improved with calcium channel blockers. Imaging appearance is typical of RCVS.

Reversible Cerebral Vasoconstriction Syndrome In the same patient, CT shows left-sided SAH , and DWI MR shows a single punctate recent infarct . There was no T2 signal or vessel wall enhancement on DANTE T1 SPACE . Diagnosis was RCVS.

Vasculitis DSA in a 40-year-old patient with recurrent strokes and eventual diagnosis of vasculitis shows subtle right middle cerebral artery (MCA) narrowing . Avid wall enhancement is present on vwMR DANTE T1 SPACE without T2 signal .

Carotid Web CTA images show linear filling defects in the posterolateral carotid bifurcation in 3 different patients , consistent with carotid webs. Carotid webs are associated with increased risk of ipsilateral ischemic infarct.

Perivascular Infection 3D TOF C+ MR in a 62-year-old man with left CNVI palsy and Horner syndrome shows left cavernous sinus thrombophlebitis and intraluminal clot in the left ICA . DSA confirms perivascular infection along the left ICA with intraluminal clot .

Perivascular Tumor A 59-year-old woman presented with left MCA infarcts on DTI but elevated CBV along the left insula . MR spectroscopy reveals elevated choline . Vessel wall enhancement is present on DANTE T1 SPACE . This was biopsy-proven GBM with MCA invasion.

Additional Images

Vasospasm In a patient with a ruptured pseudoaneurysm , DSA shows multifocal areas of vessel narrowing, consistent with vasospasm . vwMR was negative in the areas of narrowing (not shown).

Aneurysm Right ICA ophthalmic segment saccular aneurysm is shown on DSA and 3D TOF MRA . Note areas of wall enhancement comparing pre- and postcontrast DANTE T1 SPACE, thought to be linked to growth and rupture risk.

Reversible Cerebral Vasoconstriction Syndrome DSA shows multifocal areas of narrowing in a patient with thunderclap headache. Multifocal posterior circulation narrowing was also present, and vwMR was negative (not shown). The patient improved with calcium channel blockers. This was RCVS.

Vasculitis DSA in a 40-year-old patient with recurrent strokes and eventual diagnosis of vasculitis shows severe right subclavian artery narrowing . Wall enhancement is present on DANTE T1 SPACE without T2 signal .